Numerous powered devices utilize power over multi-pair Ethernet cables. The IEEE 802.3at-2009 Power-over-Ethernet (“PoE”) standard, ratified Sep. 11, 2009, defines a standardized approach for providing power over Ethernet cables.
A non-limiting example of an Ethernet cable is a category 5 cable. A category 5 cable includes eight wire connectors grouped into four wire pairs. Under the IEEE 802.3at-2009 PoE standard, power sourcing equipment can provide DC power over two of the four wire pairs included in the cable. Such pairs are generally referred to as a PoE powered pair or powered cable pair. Power can be injected into the powered cable pairs of a cable using Ethernet magnetics in a pair of PoE taps. A “pair of PoE taps” refers to the center taps of two of the four wire pairs in an Ethernet cable.
In PoE systems, one tap of a pair of PoE taps is used for power delivery and a second tap is used for power return. The power is injected into the center tap of the Ethernet transformer of one of the twisted pairs in the powered cable pair. The return is extracted at the center tap of the Ethernet transformer of a second twisted pair of the power cable pair. Direct current (“DC”) power can be provided over the powered cable pairs as a common mode current. Telecommunications systems can utilize the pairs in the cable as data lines. Data can be provided over one or more wire pairs as a differential signal. In some systems, power and data may be provided on the same twisted pair. The Ethernet device receiving the power and data via the Ethernet cable can include a differential input that suppresses the bias and noise associated with the common mode current. As a result, providing DC power as a common mode current reduces the interference to the data signals.
Under the IEEE 802.3at-2009 PoE standard, power sourcing equipment can provide a powered device with up to up to 25.5 watts of DC power over, for example, a category 5 twisted pair communication cable. As telecommunications devices adapt to meet new communication demands, however, such devices may have different power needs or demands. For example, as more functionality is added to communication devices and systems, such devices and systems may include powered peripheral devices that couple with or are plugged into the main communication devices. Such peripheral devices may need more than 25.5 watts of power.
Accordingly, a versatile system and method for providing PoE power to communication devices in a wireless communications system is desirable.